Cadillac CT6
The headline figure for this car is 21 MPG, but the EPA rates 2 different versions of it, from 17 to 21 MPG. Which engine and drivetrain you order is worth $417 a year in fuel — a decision made once at the dealership and paid for every week afterwards.
Your cost per mile
Every version, 2020
| Version | Combined | City | Highway | Fuel | EPA annual |
|---|---|---|---|---|---|
| 3.6L 6cyl · AWD · Auto S10 | 21 | 18 | 27 | Regular | $2,950 |
| 4.2L V8 · AWD · Auto S10 | 17 | 14 | 25 | Premium | $4,550 |
2 configurations, 17–21 MPG. 1 of 2 require or recommend premium — worth checking before you sign, because it is not something you can change afterwards.
Every model year
| Year | Combined | City | Highway |
|---|---|---|---|
| 2016 | 25 | 22 | 30 |
| 2017 | 21 | 18 | 27 |
| 2018 | 21 | 18 | 26 |
| 2019 | 21 | 18 | 27 |
| 2020 | 21 | 18 | 27 |
Straight from the EPA certification database, one row per model year, showing the best-rated version of each. Trims with identical figures are collapsed.
What owners report
| Year | Owners | Average reported | Spread |
|---|---|---|---|
| 2019 | 1 | 27.1 | 27–27 |
One owner filed these through the EPA's own My MPG tool. That is a sample, not an average — read them as anecdotes. They are here because they are the only owner-reported figures in public federal data.
How this is worked out
Cost per mile is the fuel price over the combined MPG of the version you pick, at the price and mileage you enter. Where a version requires premium, it is costed at the premium price — that is a real and permanent difference between two cars wearing the same badge.
Every figure comes from the U.S. EPA's public fuel economy data. We add no estimates of our own; a missing number shows as a dash rather than a guess.
Add your numbers
Federal data has at most a handful of owners per car and nothing at all on servicing. If you own one, send what you actually get. It goes on this page with the sample size next to it.